1. Field of the Invention
This invention relates to an improvement in the combustion chamber construction of a spark-ignition internal combustion engine, and more particularly to a combustion chamber construction improvement in a high compression ratio reciprocating piston internal combustion engine.
2. Description of the Prior Art
In internal combustion engines used for automotive vehicles, fuel consumption characteristics and economy have become important from the view points of energy saving and exhaust gas purification. In order to attain low fuel consumption characteristics, it is necessary to increase the combustion efficiency and the thermal efficiency of the engine. For this purpose, it has now known that the combustion in the combustion chambers of the engine can be improved by strengthening the swirl of intake air or by using a dual spark plug ignition. In addition, in order to increase the thermal efficiency and thereby improve fuel consumption characteristics, it has been proposed to raise the compression ratio of the engine over the conventional range of of 7.5 to 9.0.